LIS Audio March Feature – Late 70’s GMC Sierra Classic

Products

TSPEC V8GT 0 gauge Power & Ground Wire
TSPEC V8GT 4 gauge Power & Ground Wire
Kicker Q-Class 6.5 inch Convertible Components x2
Kicker L7T Slim Mount 10 inch Subwoofers x4
Kicker KXA 2400.1 Monoblock Amplifier
Kicker KXA 400.4 Four Channel Amplifier

Introduction

In the middle of last fall we had the opportunity to get our hands on this slabbed out late 70’s GMC Sierra dually truck, and yes it’s definitely riding on air. Our client wanted to change up the audio set up from what had been previously installed. On top of changing out all previous audio equipment, our client wanted to stuff as much new audio product we could possibly get in the truck without protruding into the very tight cabin.

Electrical

Starting with the power plant of this beast, the original 350 had been removed and replaced with a big block 454. The big block came with an original alternator specific to the era of the motor. This alternator in its current condition would not be enough power to sufficiently serve the Dually’s new audio system. We made our suggestion to the client to go with an aftermarket upgraded alternator. Our client accepted our suggestion, however, he has plans of doing yet another motor swap in the near future. When the new motor goes in a beefier alternator will go with it. In the meantime, we had the 454’s alternator removed and refurbished.

In the engine bay, we upgraded the old deteriorating ground wires with the TSPEC OFC 0 gauge copper wiring and used techflex 0 gauge sleeving. The sleeving helps protect the wiring from the elements and also allows the wiring to blend in. The batteries in the truck are located in the rear of the vehicle, we had to fabricate an inline fuse holder on the frame rail to secure the fuse blocks to the vehicle.

A-Pillars & Components

A-Pillars

After looking at the previous tweeter location, we knew that we needed to make a change. We decided to fabricate the new Kicker Q-Class tweeter into the A-pillar. The decision was made to move the tweeter from the headliner down to a couple of inches over the dash line. This position proved to be a better location than beaming down from the headliner.

Components

The Kicker Q-Class midwoofer was installed in the same location of the previously installed equipment. During the mid woofer fitting process we added Hushmat sound foam to the door skin directly behind where the speaker would be mounted.

The second set of Kicker Q-Class Speakers were mounted behind the bench seat between the driver and passenger opening. In the location, the speakers were set up in there coaxial form to save space.

Amplifiers, Subwoofers, & Subwoofer Enclosure

Amplifiers & Crossovers

When mounting the amplifiers and crossovers we utilized two locations. One of those locations required us to remove the cabin bench seat. Under the bench seat we were able to use a low section in the floor to squeeze the Kicker KXA 2400.1 and Q-Class Crossovers. While securing the amplifier and crossovers to the mounting surface we also ran wiring underneath the cabin carpeting for a concealed look. The Kicker KXA 400.4 found its final resting location snuggly between the two pairs of ten inch woofers on the woofer enclosure.

Subwoofers

Connected to the receiving end of the beastly KXA 2400.1 amplifier is four Kicker L7T slim mount subwoofers, These subwoofers were perfect for the application. The L7T has a mounting depth of just three and three-quarter inches with the capability of handling 500-600 watts rms per subwoofer.

Subwoofer Enclosure

For the Subwoofer enclosure we used every inch of space available without compromising a larger amount of legroom for the driver and passenger. The face of the enclosure received a double baffle along with interior bracing. These measures were taken to insure structural integrity against the four woofers receiving 2400 watts of power from the Kicker Amplifier.